I am sure you have observed that puzzle number 34 (exponentiation, page 64), A3E4, is indicating (below) 10x10 puzzle, while it's a 9x9.And puzzle number 109 (variations, page 156), A3V9, is indicating 8x8 puzzle, while it's a 6x6, so you have small corrections for the next edition .

It's a very advanced book, wonderful, some puzzles are really difficult.

I am sure you have observed that puzzle number 34 (exponentiation, page 64), A3E4, is indicating (below) 10x10 puzzle, while it's a 9x9.And puzzle number 109 (variations, page 156), A3V9, is indicating 8x8 puzzle, while it's a 6x6, so you have small corrections for the next edition

Argh, those slipped through, even after a "manual" check of each puzzle

Thanks for pointing this out.

clm wrote:

It's a very advanced book, wonderful, some puzzles are really difficult.

It's a very advanced book, wonderful, some puzzles are really difficult.

Good, if you say this, then they must be difficult indeed

That is wonderful, "difficult indeed" :j

Actually, what would be wonderful would be our esteemed clm giving us the low down on which puzzles were difficult and which really difficult :)

(I then could leave until some weird masochistic mood strikes me those delicious "really difficult", or until never, whichever comes first:)

Hi, frederick. In general, the difficulty has a subjective component, of course (I have not finished solving all puzzles in the book yet, around the 70%). I do not think the wide puzzles or the variations are the more difficult. However the large modulo, from zero and no-op could reach a really high level of difficulty.

A 10x10 no-op is a typical example of a really difficult. Let's think, for instance, that a "simple" 3-cell cage "4" has: as sum [1,1,2], as product [1,1,4] and [1,2,2], as division [1,1,4] again and [1,2,8], and as a subtraction: [1,1,6], [2,2,8], [3,3,10], [1,2,7], [1,3,8], [1,4,9], [1,5,10], [2,3,9] and [2,4,10], so 13 different combinations.

This is only my opinion (for the moment) with respect to this book.Really difficult:Puzzle 49 (A3G4, 9x9 -4 to 4 negative numbers)Puzzle 50 (A3G5, 11x11 -5 to 5 negative numbers)Puzzle 58 (A3M18, 10x10 modulo) (the harder I have found to the moment)Puzzle 62 (A3S12, 8x8 single operator modulo)Puzzle 67 (A3Z12, 7x7 from zero)Puzzle 75 (A3Z20, 10x10 from zero)